common: Add pre and de emphasis, if the radio does not support it
Connect to the oscillator of the transmitter - good girl! You need to enable pre emphasis in this case. Connect to the discriminator of the receiver - good boy! You need to enable de emphasis in this case.
This commit is contained in:
parent
5062628e52
commit
4356c93afa
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@ -24,3 +24,4 @@ src/anetz/anetz
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src/bnetz/bnetz
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src/nmt/nmt
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test/test_compander
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test/test_emphasis
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@ -137,7 +137,7 @@ static void anetz_timeout(struct timer *timer);
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static void anetz_go_idle(anetz_t *anetz);
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/* Create transceiver instance and link to a list. */
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int anetz_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume)
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int anetz_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume)
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{
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anetz_t *anetz;
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int rc;
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@ -156,7 +156,7 @@ int anetz_create(const char *sounddev, int samplerate, const char *write_wave, c
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PDEBUG(DANETZ, DEBUG_DEBUG, "Creating 'A-Netz' instance for 'Kanal' = %d (sample rate %d).\n", kanal, samplerate);
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/* init general part of transceiver */
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rc = sender_create(&anetz->sender, sounddev, samplerate, write_wave, read_wave, kanal, loopback, loss_volume, -1);
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rc = sender_create(&anetz->sender, sounddev, samplerate, pre_emphasis, de_emphasis, write_wave, read_wave, kanal, loopback, loss_volume, -1);
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if (rc < 0) {
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PDEBUG(DANETZ, DEBUG_ERROR, "Failed to init 'Sender' processing!\n");
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goto error;
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@ -41,7 +41,7 @@ typedef struct anetz {
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double anetz_kanal2freq(int kanal, int unterband);
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int anetz_init(void);
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int anetz_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume);
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int anetz_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume);
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void anetz_destroy(sender_t *sender);
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void anetz_loss_indication(anetz_t *anetz);
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void anetz_receive_tone(anetz_t *anetz, int bit);
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@ -142,7 +142,7 @@ int main(int argc, char *argv[])
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}
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/* create transceiver instance */
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rc = anetz_create(sounddev, samplerate, write_wave, read_wave, kanal, loopback, lossdetect / 100.0);
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rc = anetz_create(sounddev, samplerate, do_pre_emphasis, do_de_emphasis, write_wave, read_wave, kanal, loopback, lossdetect / 100.0);
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if (rc < 0) {
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fprintf(stderr, "Failed to create \"Sender\" instance. Quitting!\n");
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goto fail;
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@ -242,7 +242,7 @@ static void bnetz_timeout(struct timer *timer);
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static void bnetz_go_idle(bnetz_t *bnetz);
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/* Create transceiver instance and link to a list. */
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int bnetz_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int gfs, int loopback, double loss_factor, const char *pilot)
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int bnetz_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int gfs, int loopback, double loss_factor, const char *pilot)
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{
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bnetz_t *bnetz;
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int use_pilot_tone = -1;
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@ -300,7 +300,7 @@ error_pilot:
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PDEBUG(DBNETZ, DEBUG_DEBUG, "Creating 'B-Netz' instance for 'Kanal' = %d 'Gruppenfreisignal' = %d (sample rate %d).\n", kanal, gfs, samplerate);
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/* init general part of transceiver */
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rc = sender_create(&bnetz->sender, sounddev, samplerate, write_wave, read_wave, kanal, loopback, loss_factor, use_pilot_tone);
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rc = sender_create(&bnetz->sender, sounddev, samplerate, pre_emphasis, de_emphasis, write_wave, read_wave, kanal, loopback, loss_factor, use_pilot_tone);
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if (rc < 0) {
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PDEBUG(DBNETZ, DEBUG_ERROR, "Failed to init transceiver process!\n");
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goto error;
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@ -90,7 +90,7 @@ typedef struct bnetz {
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double bnetz_kanal2freq(int kanal, int unterband);
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int bnetz_init(void);
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int bnetz_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int gfs, int loopback, double loss_volume, const char *pilot);
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int bnetz_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int gfs, int loopback, double loss_volume, const char *pilot);
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void bnetz_destroy(sender_t *sender);
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void bnetz_loss_indication(bnetz_t *bnetz);
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void bnetz_receive_tone(bnetz_t *bnetz, int bit);
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@ -154,7 +154,7 @@ int main(int argc, char *argv[])
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}
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/* create transceiver instance */
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rc = bnetz_create(sounddev, samplerate, write_wave, read_wave, kanal, gfs, loopback, (double)lossdetect / 100.0, pilot);
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rc = bnetz_create(sounddev, samplerate, do_pre_emphasis, do_de_emphasis, write_wave, read_wave, kanal, gfs, loopback, (double)lossdetect / 100.0, pilot);
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if (rc < 0) {
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fprintf(stderr, "Failed to create \"Sender\" instance. Quitting!\n");
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goto fail;
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@ -18,6 +18,7 @@ libcommon_a_SOURCES = \
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../common/besetztton.c \
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../common/mncc_sock.c \
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../common/cause.c \
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../common/emphasis.c \
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../common/compander.c \
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../common/sender.c \
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../common/main_common.c
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@ -0,0 +1,102 @@
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/* Pre-Emphasis and De-Emphasis implementation
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*
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* (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
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* All Rights Reserved
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <math.h>
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#include "emphasis.h"
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#include "debug.h"
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int init_emphasis(emphasis_t *state, int samplerate)
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{
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double factor;
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memset(state, 0, sizeof(*state));
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if (samplerate < 24000) {
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PDEBUG(DDSP, DEBUG_ERROR, "Sample rate must be at least 24000 Hz!\n");
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return -1;
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}
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factor = 0.95;
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state->p.factor = factor;
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state->p.amp = samplerate / 48000.0 * 4.0; /* mysterious 48000 */
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state->d.factor = factor;
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state->d.amp = 1.0 / (samplerate / 48000.0 * 4.0); /* mysterious 48000 */
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return 0;
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}
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void pre_emphasis(emphasis_t *state, int16_t *samples, int num)
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{
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int32_t sample;
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double old_value, new_value, last_value, factor, amp;
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int i;
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last_value = state->p.last_value;
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factor = state->p.factor;
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amp = state->p.amp;
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for (i = 0; i < num; i++) {
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old_value = (double)(*samples) / 32768.0;
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new_value = old_value - factor * last_value;
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last_value = old_value;
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sample = (int)(amp * new_value * 32768.0);
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if (sample > 32767)
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sample = 32767;
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else if (sample < -32768)
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sample = -32768;
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*samples++ = sample;
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}
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state->p.last_value = last_value;
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}
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void de_emphasis(emphasis_t *state, int16_t *samples, int num)
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{
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int32_t sample;
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double old_value, new_value, last_value, factor, amp;
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int i;
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last_value = state->d.last_value;
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factor = state->d.factor;
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amp = state->d.amp;
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for (i = 0; i < num; i++) {
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old_value = (double)(*samples) / 32768.0;
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new_value = old_value + factor * last_value;
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last_value = new_value;
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sample = (int)(amp * new_value * 32768.0);
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if (sample > 32767)
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sample = 32767;
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else if (sample < -32768)
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sample = -32768;
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*samples++ = sample;
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}
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state->d.last_value = last_value;
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}
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@ -0,0 +1,17 @@
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typedef struct emphasis {
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struct {
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double last_value;
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double factor;
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double amp;
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} p;
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struct {
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double last_value;
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double factor;
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double amp;
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} d;
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} emphasis_t;
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int init_emphasis(emphasis_t *state, int samplerate);
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void pre_emphasis(emphasis_t *state, int16_t *samples, int num);
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void de_emphasis(emphasis_t *state, int16_t *samples, int num);
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@ -8,6 +8,8 @@ extern int use_mncc_sock;
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extern int send_patterns;
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extern int loopback;
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extern int rt_prio;
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extern int do_pre_emphasis;
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extern int do_de_emphasis;
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extern const char *read_wave;
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extern const char *write_wave;
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@ -36,6 +36,8 @@ int use_mncc_sock = 0;
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int send_patterns = 1;
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int loopback = 0;
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int rt_prio = 0;
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int do_pre_emphasis = 0;
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int do_de_emphasis = 0;
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const char *read_wave = NULL;
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const char *write_wave = NULL;
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@ -66,6 +68,12 @@ void print_help_common(const char *arg0, const char *ext_usage)
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printf(" Loopback test: 1 = internal | 2 = external | 3 = echo\n");
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printf(" -r --realtime <prio>\n");
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printf(" Set prio: 0 to diable, 99 for maximum (default = %d)\n", rt_prio);
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printf(" -E --pre-emphasis\n");
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printf(" Enable pre-emphasis, if you directly connect to the oscillator of the\n");
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printf(" transmitter. (No pre-emphasis done by the transmitter.)\n");
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printf(" -e --de-emphasis\n");
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printf(" Enable de-emphasis, if you directly connect to the discriminator of\n");
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printf(" the receiver. (No de-emphasis done by the receiver.)\n");
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printf(" -W --write-wave <file>\n");
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printf(" Write received audio to given wav audio file.\n");
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printf(" -R --read-wave <file>\n");
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@ -84,12 +92,14 @@ static struct option long_options_common[] = {
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{"send-patterns", 0, 0, 'p'},
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{"loopback", 1, 0, 'L'},
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{"realtime", 1, 0, 'r'},
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{"pre-emphasis", 0, 0, 'E'},
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{"de-emphasis", 0, 0, 'e'},
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{"write-wave", 1, 0, 'W'},
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{"read-wave", 1, 0, 'R'},
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{0, 0, 0, 0}
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};
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const char *optstring_common = "hD:k:d:s:c:l:mp:L:r:W:R:";
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const char *optstring_common = "hD:k:d:s:c:l:mp:L:r:EeW:R:";
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struct option *long_options;
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char *optstring;
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@ -159,6 +169,14 @@ void opt_switch_common(int c, char *arg0, int *skip_args)
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rt_prio = atoi(optarg);
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*skip_args += 2;
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break;
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case 'E':
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do_pre_emphasis = 1;
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*skip_args += 1;
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break;
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case 'e':
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do_de_emphasis = 1;
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*skip_args += 1;
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break;
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case 'W':
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write_wave = strdup(optarg);
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*skip_args += 2;
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@ -32,13 +32,15 @@ sender_t *sender_head = NULL;
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static sender_t **sender_tailp = &sender_head;
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/* Init transceiver instance and link to list of transceivers. */
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int sender_create(sender_t *sender, const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume, int use_pilot_signal)
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int sender_create(sender_t *sender, const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume, int use_pilot_signal)
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{
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int rc = 0;
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PDEBUG(DSENDER, DEBUG_DEBUG, "Creating 'Sender' instance\n");
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sender->samplerate = samplerate;
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sender->pre_emphasis = pre_emphasis;
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sender->de_emphasis = de_emphasis;
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sender->kanal = kanal;
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sender->loopback = loopback;
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sender->loss_volume = loss_volume;
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@ -80,6 +82,10 @@ int sender_create(sender_t *sender, const char *sounddev, int samplerate, const
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}
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}
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rc = init_emphasis(&sender->estate, samplerate);
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if (rc < 0)
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goto error;
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*sender_tailp = sender;
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sender_tailp = &sender->next;
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@ -151,6 +157,8 @@ void process_sender(sender_t *sender, int latspl)
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jitter_load(&sender->audio, samples, count);
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else
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sender_send(sender, samples, count);
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if (sender->pre_emphasis)
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pre_emphasis(&sender->estate, samples, count);
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switch (sender->use_pilot_signal) {
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case 2:
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/* tone if pilot signal is on */
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@ -201,6 +209,8 @@ void process_sender(sender_t *sender, int latspl)
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return;
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}
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if (count) {
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if (sender->de_emphasis)
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de_emphasis(&sender->estate, samples, count);
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if (sender->wave_play.fp)
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wave_read(&sender->wave_play, samples, count);
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if (sender->loopback != 1) {
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@ -3,6 +3,7 @@
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#include "samplerate.h"
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#include "jitter.h"
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#include "loss.h"
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#include "emphasis.h"
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/* common structure of each transmitter */
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typedef struct sender {
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@ -18,6 +19,9 @@ typedef struct sender {
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void *sound;
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int samplerate;
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samplerate_t srstate; /* sample rate conversion state */
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int pre_emphasis; /* use pre_emhasis, done by sender */
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int de_emphasis; /* use de_emhasis, done by sender */
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emphasis_t estate; /* pre and de emphasis */
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/* loopback test */
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int loopback; /* 0 = off, 1 = internal, 2 = external */
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@ -47,7 +51,7 @@ typedef struct sender {
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/* list of all senders */
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extern sender_t *sender_head;
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int sender_create(sender_t *sender, const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume, int use_pilot_signal);
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int sender_create(sender_t *sender, const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int kanal, int loopback, double loss_volume, int use_pilot_signal);
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void sender_destroy(sender_t *sender);
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void sender_send(sender_t *sender, int16_t *samples, int count);
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void sender_receive(sender_t *sender, int16_t *samples, int count);
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@ -33,7 +33,7 @@
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#define PI M_PI
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/* signalling */
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#define TX_AUDIO_0dBm0 16384 /* works quite well */
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#define TX_AUDIO_0dBm0 32767 /* works quite well */
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#define TX_PEAK_FSK 16384.0 /* peak amplitude of signalling FSK */
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#define TX_PEAK_SUPER 1638.0 /* peak amplitude of supervisory signal */
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#define BIT_RATE 1200 /* baud rate */
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@ -467,8 +467,7 @@ void sender_receive(sender_t *sender, int16_t *samples, int length)
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spl = nmt->sender.rxbuf;
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pos = nmt->sender.rxbuf_pos;
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for (i = 0; i < count; i++) {
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#warning hacking: remove after preemphasis implementation
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spl[pos++] = down[i] / 2;
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spl[pos++] = down[i];
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if (pos == 160) {
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call_tx_audio(nmt->sender.callref, spl, 160);
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pos = 0;
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@ -239,7 +239,7 @@ int main(int argc, char *argv[])
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}
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/* create transceiver instance */
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rc = nmt_create(sounddev, samplerate, write_wave, read_wave, kanal, (loopback) ? CHAN_TYPE_TEST : chan_type, ms_power, nmt_digits2value(traffic_area, 2), area_no, compander, supervisory, loopback);
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rc = nmt_create(sounddev, samplerate, do_pre_emphasis, do_de_emphasis, write_wave, read_wave, kanal, (loopback) ? CHAN_TYPE_TEST : chan_type, ms_power, nmt_digits2value(traffic_area, 2), area_no, compander, supervisory, loopback);
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if (rc < 0) {
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fprintf(stderr, "Failed to create transceiver instance. Quitting!\n");
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goto fail;
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@ -283,7 +283,7 @@ static void nmt_timeout(struct timer *timer);
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static void nmt_go_idle(nmt_t *nmt);
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/* Create transceiver instance and link to a list. */
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int nmt_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int channel, enum nmt_chan_type chan_type, uint8_t ms_power, uint8_t traffic_area, uint8_t area_no, int compander, int supervisory, int loopback)
|
||||
int nmt_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int channel, enum nmt_chan_type chan_type, uint8_t ms_power, uint8_t traffic_area, uint8_t area_no, int compander, int supervisory, int loopback)
|
||||
{
|
||||
nmt_t *nmt;
|
||||
int rc;
|
||||
|
@ -324,7 +324,7 @@ int nmt_create(const char *sounddev, int samplerate, const char *write_wave, con
|
|||
PDEBUG(DNMT, DEBUG_DEBUG, "Creating 'NMT' instance for channel = %d (sample rate %d).\n", channel, samplerate);
|
||||
|
||||
/* init general part of transceiver */
|
||||
rc = sender_create(&nmt->sender, sounddev, samplerate, write_wave, read_wave, channel, loopback, 0, -1);
|
||||
rc = sender_create(&nmt->sender, sounddev, samplerate, pre_emphasis, de_emphasis, write_wave, read_wave, channel, loopback, 0, -1);
|
||||
if (rc < 0) {
|
||||
PDEBUG(DNMT, DEBUG_ERROR, "Failed to init transceiver process!\n");
|
||||
goto error;
|
||||
|
|
|
@ -134,7 +134,7 @@ const char *chan_type_long_name(enum nmt_chan_type chan_type);
|
|||
double nmt_channel2freq(int channel, int uplink);
|
||||
void nmt_country_list(void);
|
||||
uint8_t nmt_country_by_short_name(const char *short_name);
|
||||
int nmt_create(const char *sounddev, int samplerate, const char *write_wave, const char *read_wave, int channel, enum nmt_chan_type chan_type, uint8_t ms_power, uint8_t traffic_area, uint8_t area_no, int compander, int supervisory, int loopback);
|
||||
int nmt_create(const char *sounddev, int samplerate, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int channel, enum nmt_chan_type chan_type, uint8_t ms_power, uint8_t traffic_area, uint8_t area_no, int compander, int supervisory, int loopback);
|
||||
void nmt_destroy(sender_t *sender);
|
||||
void nmt_receive_frame(nmt_t *nmt, const char *bits, double quality, double level, double frames_elapsed);
|
||||
const char *nmt_get_frame(nmt_t *nmt);
|
||||
|
|
|
@ -1,7 +1,8 @@
|
|||
AM_CPPFLAGS = -Wall -g $(all_includes)
|
||||
|
||||
noinst_PROGRAMS = \
|
||||
test_compander
|
||||
test_compander \
|
||||
test_emphasis
|
||||
|
||||
test_compander_SOURCES = test_compander.c
|
||||
|
||||
|
@ -10,3 +11,10 @@ test_compander_LDADD = \
|
|||
$(top_builddir)/src/common/libcommon.a \
|
||||
-lm
|
||||
|
||||
test_emphasis_SOURCES = test_emphasis.c
|
||||
|
||||
test_emphasis_LDADD = \
|
||||
$(COMMON_LA) \
|
||||
$(top_builddir)/src/common/libcommon.a \
|
||||
-lm
|
||||
|
||||
|
|
|
@ -0,0 +1,75 @@
|
|||
#include <stdio.h>
|
||||
#include <stdint.h>
|
||||
#include <math.h>
|
||||
#include <string.h>
|
||||
#include "../common/emphasis.h"
|
||||
|
||||
#define level2db(level) (20 * log10(level))
|
||||
#define db2level(db) pow(10, (double)db / 20.0)
|
||||
|
||||
#define SAMPLERATE 48000
|
||||
#define DEVIATION 8000.0
|
||||
|
||||
static void check_level(int16_t *samples, const char *desc)
|
||||
{
|
||||
int i;
|
||||
int last = 0, envelope = 0;
|
||||
int up = 0;
|
||||
int freq;
|
||||
|
||||
for (i = 0; i < SAMPLERATE; i++) {
|
||||
if (last < samples[i]) {
|
||||
up = 1;
|
||||
} else if (last > samples[i]) {
|
||||
if (up) {
|
||||
envelope = last;
|
||||
}
|
||||
up = 0;
|
||||
}
|
||||
if ((i % (SAMPLERATE/40)) == 0) {
|
||||
freq = 500 + 500 * (i / (SAMPLERATE / 8));
|
||||
printf("%s: f = %d envelop = %.4f\n", desc, freq, level2db((double)envelope / DEVIATION));
|
||||
}
|
||||
last = samples[i];
|
||||
}
|
||||
}
|
||||
|
||||
static void gen_samples(int16_t *samples)
|
||||
{
|
||||
int i;
|
||||
double value;
|
||||
int freq;
|
||||
|
||||
for (i = 0; i < SAMPLERATE; i++) {
|
||||
freq = 500 + 500 * (i / (SAMPLERATE / 8));
|
||||
value = sin(2.0 * M_PI * (double)freq / (double)SAMPLERATE * (double)i);
|
||||
samples[i] = value * DEVIATION;
|
||||
}
|
||||
}
|
||||
|
||||
int main(void)
|
||||
{
|
||||
emphasis_t estate;
|
||||
int16_t samples[SAMPLERATE];
|
||||
|
||||
/* generate sweep 0..4khz */
|
||||
gen_samples(samples);
|
||||
|
||||
init_emphasis(&estate, SAMPLERATE);
|
||||
|
||||
// check_level(samples, "unchanged");
|
||||
|
||||
pre_emphasis(&estate, samples, SAMPLERATE);
|
||||
|
||||
check_level(samples, "pre-emphasis");
|
||||
|
||||
/* generate sweep 0..4khz */
|
||||
gen_samples(samples);
|
||||
|
||||
de_emphasis(&estate, samples, SAMPLERATE);
|
||||
|
||||
check_level(samples, "de-emphasis");
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
Loading…
Reference in New Issue